1. Field of Invention
This invention relates generally to pumps, and more specifically to magnetically driven pumps for cooling electronic equipment and in particular computer systems.
2. Background
Heat generation occurs within an integrated circuit in response to current flow. A computer contains integrated circuits that generate heat while the computer is in an on state. As a computer""s central processing unit (CPU) clock frequency has risen, heat generation has also increased. Liquid cooling of a computer system is a highly effective means of removing heat generated by electronic devices such as a computer""s CPU. Liquid cooling systems are typically made of a closed fluid loop with a pump to circulate fluid within the loop. Coupled to the loop is a means of transferring heat into the fluid and a means of transferring heat out of the fluid.
What is lacking in the art is a suitable pump for use with electronic devices and in particular computer systems. It is desirable that a pump used in computer system cooling applications be of small volume, on the order of three cubic inches. The pump should have a flow rate between 0.5-1.5 liters/minute, provide a differential pressure of approximately 2 pounds/square inch (psi), provide less than 1 percent failure after 7 years of operation, and emit a sound level that is less than the sound emission provided by the computer system to be cooled.
In addition to these requirements are high efficiency and reliability. Existing diaphragm pumps exhibit problems with noise and reliability. Diaphragms are constantly under a state of stress, which leads to diaphragm failure. Centrifugal pumps are not efficient at low speed and become noisy at high speed with wear increasing as well. Motor driven piston pumps exhibit problems with reliability due to the multitude of moving parts required with these designs. Gear pumps suffer from problems similar to those of centrifugal pumps.